388077-33-6Relevant academic research and scientific papers
Stereoselective ZrCl4-Catalyzed Mannich-type Reaction of β-Keto Esters with Chiral Trifluoromethyl Aldimines
Parise, Luca,Pellacani, Lucio,Sciubba, Fabio,Trulli, Laura,Fioravanti, Stefania
, p. 8300 - 8306 (2015)
A method for the synthesis of fluorinated β′-amino β-dicarbonyl compounds using a Zr-catalyzed Mannich-type reaction has been developed, starting from N-protected trifluoromethyl aldimines and cyclic or acyclic β-keto esters bearing different ester residues. The in situ generated metallic complex reacted with optically pure trifluoromethyl aldimine derived from (R)-α-methylbenzylamine, giving a highly diastereoselective asymmetric Mannich-type addition with formation of a chiral quaternary center. The absolute configuration at the new chiral centers was assigned through two-dimensional nuclear Overhauser effect spectroscopic analysis coupled with computational studies.
Cerium-Catalyzed C-H Functionalizations of Alkanes Utilizing Alcohols as Hydrogen Atom Transfer Agents
An, Qing,Chen, Yuegang,Liu, Weimin,Pan, Hui,Wang, Xin,Wang, Ziyu,Zhang, Kaining,Zuo, Zhiwei
supporting information, p. 6216 - 6226 (2020/04/27)
Modern photoredox catalysis has traditionally relied upon metal-to-ligand charge-transfer (MLCT) excitation of metal polypyridyl complexes for the utilization of light energy for the activation of organic substrates. Here, we demonstrate the catalytic application of ligand-to-metal charge-transfer (LMCT) excitation of cerium alkoxide complexes for the facile activation of alkanes utilizing abundant and inexpensive cerium trichloride as the catalyst. As demonstrated by cerium-catalyzed C-H amination and the alkylation of hydrocarbons, this reaction manifold has enabled the facile use of abundant alcohols as practical and selective hydrogen atom transfer (HAT) agents via the direct access of energetically challenging alkoxy radicals. Furthermore, the LMCT excitation event has been investigated through a series of spectroscopic experiments, revealing a rapid bond homolysis process and an effective production of alkoxy radicals, collectively ruling out the LMCT/homolysis event as the rate-determining step of this C-H functionalization.
Dehydroxymethylation of alcohols enabled by cerium photocatalysis
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information, p. 10556 - 10564 (2019/08/20)
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Dehydroxymethylation of Alcohols Enabled by Cerium Photocatalysis
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information, p. 10556 - 10564 (2019/08/28)
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Enantioselective friedel-crafts alkylation of indoles with trifluoroethylidene malonates by copper-bis(oxazoline) complexes: Construction of trifluoromethyl-substituted stereogenic tertiary carbon center
Wen, Lele,Shen, Qilong,Wan, Xiaolong,Lu, Long
supporting information; experimental part, p. 2282 - 2285 (2011/05/17)
An enantioselective alkylation of indoles with trifluoroethylidene malonates catalyzed by copper(II)-bis (oxazoline) complexes has been developed. The expected adducts with a stereogenic tertiary carbon center bearing a trifluoromethyl group were obtained
Enantioselective organocatalytic Michael addition of aldehydes to trifluoroethylidene malonates
Wen, Lele,Shen, Qilong,Lu, Long
supporting information; experimental part, p. 4655 - 4657 (2010/12/19)
An efficient, highly enantioselective, organocatalytic Michael addition reaction of aldehydes with trifluoroethylidene malonates is described. The asymmetric reaction provided highly optically pure β-trifluoromethyl aldehydes which can be conveniently tra
New synthesis of 2-trifluoromethyl-2,3-dihydro-1H-quinolin-4-ones
Gong, Yuefa,Kato, Katsuya
, p. 767 - 773 (2007/10/03)
N-(1-Ethoxy-2,2,2-trifluoroethyl)anilines 2a-2f, prepared from trifluoroacetaldehyde ethyl hemiacetal and aniline, readily reacted with diethyl malonate in the presence of sodium hydride, giving substituted products 5a-5f in high yields. Compounds 5a-5f s
Nucleophilic reactions with α-trifluoromethyl imine and N,O-disubstituted aminal: Synthesis of β-trifluoromethyl β-anilino esters
Gong, Yuefa,Kato, Katsuya
, p. 77 - 80 (2007/10/03)
The Reformatsky reaction with 4-methoxy-N-(2,2,2-trifluoroethylidene)aniline (1) proceeds under mild conditions to yield ethyl 4,4,4-trifluoro-3-(N-4-methoxyphenyl)amino-2-alkylbutyrate (5) and 4-trifluoromethyl-3-alkyl-1-(4-methoxyphenyl)-2-azetidinone (
